1. Field of the Invention
The present invention relates to an antenna, and more particularly to an antenna with anti-interference characteristic for use in a portable electrical device.
2. The Related Art
With the rapid development of wireless communication technologies, portable electrical devices used in wireless communication, such as mobile phone, wireless personal digital assistant (PDA) and laptop computer, are developed and produced, and antennas employed in the respective portable electrical devices are main parts to give influence to the wireless communication performance of the portable electrical devices, especially in the portable electrical devices with small volume yet multifunction.
However, since a conventional antenna is mounted in a small space of a portable electrical device, the conventional antenna increases the vulnerability to the electromagnetic interference from the ambient environment, that is, the conventional antenna is easy to get influenced by neighbor electrical components, for example acoustic component. As a result, the resonant frequency of the conventional antenna is changed adversely or its radiation characteristic deteriorates and consequently, wireless communication quality of the portable electrical device falls seriously.